Forensic Toxicology

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Forensic Toxicology

• 11.20.08

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Deaths Investigated by Forensic Toxicologists

• Accidental Poisonings
• Drug Abuse Cases
• Suicidal Poisonings
• Homicidal Poisonings

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Main Questions Addressed by Forensic Toxicologist

• Is a drug or poison present? If so, what is the
  substance?
• How much of the substance is present? Is the
  concentration great enough to cause or contribute
  to death?
• How was the drug/poison administered?

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Properties of Ideal Poison

• Undetectable by senses
• Soluble in water
• Delayed effect
• Easily obtained
• Non-traceable
• Symptoms mimic actual disease
• Undetectable by scientific instruments
• Potent

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Potencies of Various Poisons

• Agent
• Botulinum toxin
• Ricin
• Strychnine
• Sodium arsenite
• Sodium cyanide
• Thallium

• Lethal Dose
• 0.05 mg
• 0.5 mg
• 100 mg
• 200 mg
• 250 mg
• 1000 mg

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General Classes of Poisons

• Gases HCN, CO
• Metallic Poisons As, Sb, Pb, Li, Hg, Tl
• Non-volatile organics
• Corrosive poisons strong acids/bases
• Salts NaCN
• Alkaloids
• Pesticides

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Carbon Monoxide (CO)

• Normal level of 1-3 in body (up to 10 in
  smokers)
• Fatal level at autopsy considered to be gt50 for
  a healthy middle-aged male
• CO prevents Oxygen binding to hemoglobin (red
  blood cells)
• Leads to suffocation
• CO victims have cherry pink color

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Metal Poisons

• Most common As2O3 (arsenic)
• Death within 24 hours
• Can be given in trace amounts over long periods
  of time
• Symptoms
• Vomiting
• Diarrhea

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Alkaloids

• Nitrogen-containing organic base
• Found in Plants and fungi
• Strychnine most common
• Death from muscle over-contraction, leading to
  respiratory system failure
• Spasms and convulsions

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Pesticides

• Many (most?) of the pesticides we spray on our
  lawns, gardens, etc. are poisonous
• Growing in popularity
• Easy to obtain
• Common enough that it wont raise suspicions as
  quickly if traces found

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Toxicological Analysis of Tissues

1. Collect sample of all body fluids
2. Collect samples from organs and tissues
3. Begin analysis as quickly as possible after death
   due to quick metabolism of toxins
4. Look for traces of poison OR their metabolic
   product (what toxin is changed into when broken
   down)

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Samples Collected at Autopsy

• Fluids
• Blood up to 100mL
• Urine 100 mL
• Bile all available
• Vitreous all available
• Gastric contents 50g

• Soft Tissue
• Liver 100g
• Brain 100-200g
• Kidney 50g
• Lung 50g
• Spleen 50g

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Intentional Poisoning Trends

• Perpetrator Profile
• Caucasian
• Male
• Average or above IQ
• Underachiever
• Personality defect
• Non-confrontational
• Non-athletic
• Neat, orderly, meticulous
• Loner

• Gender
• Male 46
• Female 39
• Unknown 16

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Top 5 Homicidal Poisons

• Arsenic 31
• Cyanide 9
• Strychnine 6
• Morphine 3
• Chloroform 3

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Possible Symptoms

• Constricted/dilated pupils (opioids, organic
  phosphates)
• Breath odor (arsenic smells of garlic)
• Hair loss (Thallium)
• Convulsions (strychnine)
• Paralysis (botulism)
• Coma (depressants, hypnotics)
• Skin color (COred, nitritesblue)
• Skin appearance
• (arsenic hyperkeratosis, warts)
• (dioxin chloracne)

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TCDD (dioxin) Chloracne Poisoning of Victor
Yushchenko just before Ukraine presidential
election
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